fix(federation): always set server status to OK after successful runs

fix(federation): always set server status to OK after successful runs

Previously if a server status got set to failure, it stayed that way
until an addressbook-sync found changes. Now the server status is set to
OK after each successful sync check (if that's not the case already),
regardless of addressbook changes.

This change also includes two new logging statements, which could help
next time someone debugs this.

Signed-off-by: Pablo Zimdahl <pablo@nextcloud.com>